AP LOS ANGELES -- A judge on Tuesday ordered the personal physician of Michael Jackson to stand trial for involuntary manslaughter after hearing testimony that he administered a lethal dose of a powerful anesthetic and other sedatives then left the pop star alone.

The ruling in the case against Houston cardiologist Dr. Conrad Murray came after a six-day preliminary hearing before Superior Court Judge Michael Pastor.

Prosecutors concluded their case with testimony from two doctors who said Murray acted outside the standard of medical care when he administered the propofol then failed to provide proper care.

Both witnesses said that even if Jackson had self-administered the final dose of the drug, his death would be a homicide because of Murray's actions.

Murray, 57, has pleaded not guilty, and his attorneys have said he did not give Jackson anything that should have killed him. Murray could face up to four years in prison if tried and convicted.

During closing arguments at the hearing, Murray's defense attorney, Joseph Low IV, argued the case should be dismissed because prosecutors didn't adequately prove how Murray caused Jackson's death. He also said Jackson's health may have been a contributing cause.

"In contrast to Mr. Low's comment, let me just say, it was not Michael Jackson's time to go," Deputy District Attorney David Walgren said. "Because of Dr. Murray's actions, Michael's children are left without a father."

During the hearing, prosecutors built a timeline of Jackson's final hours and Murray's actions, suggesting the singer died because of Murray's gross negligence.

Though many details were previously revealed in court filings and accounts from law enforcement officials, the hearing featured new disclosures and compelling moments such as Jackson's burly former bodyguard choking back tears as he recalled the two oldest Jackson children watching their father in his death throes.

The guard, Alberto Alvarez, said daughter Paris fell to the ground crying out, "Daddy!" before Alvarez led them from the room.

Jackson's mother, Katherine, seated in the courtroom, dabbed at her eyes during the testimony. The famous Jackson siblings - Janet, Jackie, LaToya, Randy and Rebbie - were present every day along with their parents.

Alvarez also testified that Murray instructed him to place medicine vials in bags before calling 911 on the day Jackson died.

Police Detective Orlando Martinez said Murray told him he found Jackson not breathing just after 11 a.m. on June 25, 2009. Phone records showed 911 was not called until 12:21 p.m.

Paramedics and an emergency room doctor all testified that they thought Jackson died in his bedroom, before he was transported to a hospital where Murray insisted resuscitation efforts continue.

The medical personnel also said Murray didn't tell them he had given Jackson propofol, which is normally administered in hospital settings.

Using phone records and testimony from Murray's current and former girlfriends, prosecutors also showed the doctor was on the phone before and after he gave Jackson the lethal dose of propofol and sedatives.

Martinez testified about the timeline Murray laid out in a nearly three-hour interview with police two days after Jackson died.

Murray described a nearly 10-hour ordeal of trying to get Jackson to sleep, giving him a valium pill and two other sedatives intravenously before yielding to the singer's demands for propofol.

Jackson called the anesthetic his "milk," and coroner's investigators later found several vials of it in a bag labeled "Baby Essentials" in Jackson's closet.

Martinez said Jackson told Murray if he couldn't get sleep, he might have to cancel his widely heralded "This is It" comeback tour. The doctor spoke of feeling pressured to give the star the propofol he wanted, the detective said.

Defense attorneys rarely call witnesses or present their own theories during preliminary hearings, which have a lower standard of proof than criminal trials.

But lawyers for Murray did reveal possible trial strategies while questioning witnesses.

Defense attorney Ed Chernoff challenged Alvarez's recollection of events in Jackson's bedroom but stopped short of asking if there was enough time for him to do everything he said he did before dialing 911.

Another defense attorney, J. Michael Flanagan, quizzed a coroner's investigator about whether a syringe and an empty vial of propofol found under a table next to Jackson's bed, were within reach of the singer.

The judge barred an answer after a prosecutor objected.

Under Chernoff's questioning, Martinez said Murray recalled Jackson asking to self-administer propofol. Prosecutors said they expect the defense to claim Jackson administered the deadly dose himself while Murray was out of the room.

The testimony painted a troubled portrait of a singer who had grown more reclusive since his 2005 acquittal on child molestation charges. He was plagued by insomnia, and the choreographer of his show said he seemed ill and "lost" a few days before the final rehearsals but rallied to do "fabulous" work in the final two days

Jackson had been receiving propofol intravenously six nights a week for the two months before his death, Murray told detectives.

Jackson's family and fans have contended the doctor should be tried for murder. During the hearing, a plane flew over the courthouse trailing a banner with Jackson's image that read, "Change the Charge to Murder."